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Coast Guard working on ways to prevent whale-ship collisions

By Nadia Drake

Mercury News Correspondent

Posted:
11/29/2010 05:29:26 PM PST

Updated:
01/30/2011 11:31:21 PM PST

Click photo to enlarge

Port of Oakland workers, far right, look at a dead whale laying across the bow of the container ship Northern Vitality, docked at the Port, Calif., Thursday, Sept. 16, 2010. Officials from the Port and the Army Corps of Engineers are investigating how the whale came to be hit by the ship, apparently in the open ocean. (D. Ross Cameron/Staff)

Blue whales are the largest animals on the planet. An adult whale weighs hundreds of thousands of pounds -- the weight of 30 elephants -- and can be as long as three school buses.

But the majestic creatures are no match for the behemoth cargo ships speeding along the Northern California coast.

Since July, at least five whales have been killed by ships in local waters -- the same number killed over the previous five years combined. The toll includes a mother blue whale and her fetus, which washed ashore in Pescadero. A fin whale washed ashore at Ocean Beach with a crumpled spine, and what scientists believe was another fin was dragged headless into the Port of Oakland across the bow of a cargo ship. A humpback was spotted floating near the Farallon Islands with crisscrossing propeller gouges.

What's behind the rise in the deadly encounters between the giants at sea is surprisingly puny: Whales are following a bumper crop of krill -- tiny shrimplike organisms -- right into the paths of high-traffic shipping lanes outside the ports of Oakland and San Francisco. As a result, government agencies such as the U.S. Coast Guard are now considering changing the lanes and other ship traffic rules to keep the endangered mammals safe.

Zeke Grader, executive director of the Pacific Coast Federation of Fishermen's Associations, said marine life overall is a sight to behold this year. "When something like krill blooms, it affects everything else in the food chain," Grader said. "Fishermen with 40 or 50 years of experience -- old salty hands -- are telling me it's like nothing they've ever seen before."

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This past summer and fall, "the whales were phenomenal -- absolutely phenomenal," said Roger Thomas, captain of the whale-watching vessel The Salty Lady.

More deaths likely

Marine biologists say the increased sightings don't reflect a rebound in whale populations, but rather a shift in where whales spend time.

The number of whales killed is probably higher than reported. Unlike terrestrial mammals strewed across the highway, dead marine mammals rarely stick around as evidence of collisions.

"What we do see is likely to be a fraction of the total number," said John Calambokidis, a scientist with the Cascadia Research Collective in Olympia, Wash. "A lot go undocumented."

Blue whale carcasses, for example, are less likely than gray or right whales to ride the waves to a nearby beach. "Blue whales sink," he said. "They could drift offshore, be scavenged, drift out to sea."

Nutrient-rich upwellings from the sea floor are fueling a resurgence in krill, the crunchy crustacean that is the whales' favorite snack, said Baldo Marinovic, a UC Santa Cruz research biologist.

He said one particular species of krill in California's waters is skyrocketing. The species, Thysanoessa spinifera, is bigger and fattier than other shrimplike creatures, making it a better meal selection. "Pound for pound, the whales get a better bang for their buck," Marinovic said.

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Thysanoessa congregate near the continental shelf drop-off and canyon ledges such as those in Monterey Bay, he said. But dining at the continental shelf buffet puts whales directly into shipping lanes.

Three lanes direct traffic to the San Francisco and Oakland ports -- and they all pass through or near national marine sanctuaries.

"This problem is not going to go away," said Jackie Dragon, marine sanctuaries director for Pacific Environment, a San Francisco nonprofit. "Ship traffic is predicted to double by 2050."

One way to mitigate ship strikes is to decrease speeds through vulnerable areas, Dragon said. Ships currently move through sanctuaries at speeds up to 25 knots, or just under 29 mph. Pacific Environment has asked the Coast Guard to cap speeds at 10 knots.

Noting that the cargo ships often go slower to save fuel, Dragon said: "If the industry can slow down when they need to save a dime, they can slow down when we need to save endangered whales."

John Berge, vice president of the Pacific Merchant Shipping Association, said lowering the speed limit could present a potential navigation hazard. Still, the industry has not ruled out that option.

Solutions elusive

Recent research supports the theory that faster-moving ships are more likely to pull whales toward the hull or suck others that swim beneath ships into propellers.

But Calambokidis isn't convinced that getting ships to slow down is the answer. "Slower speeds mean longer times when ships are transiting areas with whales," he said, noting that a blue whale was killed last year near Fort Bragg by a ship traveling at only 5.5 knots. Calambokidis also pointed out that some whales have been observed spending more time at the surface when a ship is in the area -- not avoiding it.

Other ideas include posting marine observers on ships and extending the western shipping lane beyond the continental shelf break.

"We hope all the greater minds out there can come up with some really sound science and sound solutions," Berge said. "None of us wants to hit a whale, just like nobody driving down the highway wants to hit a deer."

TIME TO CHANGE LANES?

The U.S. Coast Guard is conducting a study to determine whether modifications to shipping lanes near San Francisco are necessary. Last year, a similar study prompted new regulations in shipping corridors along the Eastern Seaboard after a rise in the number of whale deaths from ship strikes. The Coast Guard is soliciting public comments until Jan. 20 at www.regulations.gov; enter keyword "2009-0576."